Php方程：变量减去相同的舍入变量，可能吗？

Question

I need to echo number(variable) in two ways and i need help with code for this equation. Example:

Variable is 5003

First echo has to be: 5000 (rounded)

Second echo has to be just the rounded digits: 3

So i want to know if and how can i achieve this equation, im thinking among lines of: variable(5003) minus rounded variable(5000) equals 3

So that way if variable is lets say 15009

Fist will be 15000 Second will be 9

I hope this make sense, thank you for help

Answer 1

You should look into the round^PHP function:

You can have negative decimal points like this:

round(5003, -3);  // returns 5000
round(15009, -3); // returns 15000

To figure out the difference you can do like this:

$input = 5003
$x = $input;
$y = round($input, -3);
$z = $x - $y; // z is now 3

PHP is not a mathematical language, so it cannot solve equations for you.

You can make a more general solution like this:

$inputs = [
    5003,
    15009,
    55108,
    102010
];

foreach ($inputs as $input) {
    $decimals = floor(log10($input)) - 1;
    $rounded = round($input, -1 * $decimals);
    echo "$input - $rounded = " . ($input - $rounded) . PHP_EOL;
}

Outputs:

5003 - 5000 = 3
15009 - 15000 = 9
55108 - 55000 = 108
102010 - 100000 = 2010